Archaeological investigations undertaken below the 19th century palazzo Donnaregina, prior to the creation of the Naples Museum of Contemporary Art (“Madre”), produced important results.

On via Settembrini the palace façade followed the line of the northern fortifications dating from the Greek period, which functioned as a buttress to the scarp of the deep valley below the present via Foria. A short stretch of the fortifications was uncovered, revealing the earliest curtain wall, probably of the 5th century B.C., in blocks of yellow Neapolitan tufa laid as orthostats joining to the scarp directly behind with transverse tie courses. At circa 3.00 m further north a later curtain wall, of yellow tufa blocks laid in horizontal levels, doubled the width the existing curtain wall towards the exterior, abutting it with new tie courses. The second wall appeared to have been constructed during the 4th century B.C. It was only possible to see the interior face of the new curtain wall, characterized by the presence of numerous quarry marks.

In the various points investigated the ancient ground levels from the Graeco-Roman, proto-historic and in part the prehistoric period were missing. Only those covered by the Agnano-Montespina (4100 b.p.) eruption were preserved. An agricultural surface emerged below the material from this eruption, characterised by the presence of plough furrows. This data is an important addition to knowledge regarding the original settlement phases on the plateau on which Neapolis was built centuries later.

The eruptive stratigraphy found at the southern end of the palace was cut by circular wells or middens of late Hellenistic date and large pits containing building materials. The latter were datable to a period between the 1st and 2nd century A.D. and probably related to the destruction attributed to the earthquake of 62 A.D.